Since the thermocouple, more precisely its measurement point, does not perform any temperature measurements on the surface of the component but quasi only dips into the component in the recess of the component in this arrangement, such temperature sensors are also called “immersion temperature sensors.” They are known, for example, from CH 689 875 A5 and DE 20 2011 004 481.
Practice has shown that the measurement results obtained with such a temperature sensor depend very sensitively on where in the interior of the recess of the component the measurement point of the thermocouple is located. Reproducible positioning of the measurement point of the thermocouple in a position in which it has the most intimate thermal contact possible with at least one wall surface of the recess, especially with the bottom thereof, so that the best possible heat transfer is possible from the wall surfaces of the recess to the measurement point, is desirable in this case, in particular.
Temperature sensors are available commercially, in which an attempt is made at defining the position of the measurement point of the thermocouple more precisely such that a metal jacket is arranged on the contact surface of the holder or at least such that said jacket passes partly through said contact surface, such that an interior of the metal jacket is connected through the opening to the side of the holder located opposite the contact surface. The shape of this metal jacket is adapted to the shape of the recess of the component such that the most precise fit possible is obtained. The section of the thermocouple that has the measurement point is inserted into the interior of the metal jacket.
This embodiment of the temperature sensor makes it possible, in particular, to arrange and possibly fix the measurement point before the installation of the temperature sensor on the components at a desired location in the interior of the metal jacket. This is especially true if the metal jacket has an opening on the side located opposite the contact surface of the holder, as in the case of, e.g., a sleeve.
However, the positioning of the measurement point in a given position in the interior of the metal jacket cannot guarantee per se that there indeed is a good thermal contact with the bottom. In addition, it is seen that even though sufficiently good thermal conduction is achieved with the metal jacket from the wall surface of the recess in the component to be heated to the jacket surfaces of the metal jacket, which jacket surfaces define the interior of the metal jacket, there is no sufficiently good heat transfer from these jacket surfaces to the measurement point of the thermocouple. It was therefore found during the practical use of such temperature sensors that even though they lead to an improvement in the reliability of the temperature data determined with them, there still is a need for improvement.
In addition, the response characteristic, i.e., the time elapsing until a change in temperature becomes established, needs to be improved.